U.S. patent number 8,362,677 [Application Number 12/768,887] was granted by the patent office on 2013-01-29 for high efficiency thermal management system for solid state lighting device.
This patent grant is currently assigned to LEDnovation, Inc.. The grantee listed for this patent is Thong Bui, Israel Morejon, Evan O'Sullivan, Jeremy Swiger, Jinhui Zhai. Invention is credited to Thong Bui, Israel Morejon, Evan O'Sullivan, Jeremy Swiger, Jinhui Zhai.
United States Patent |
8,362,677 |
Morejon , et al. |
January 29, 2013 |
High efficiency thermal management system for solid state lighting
device
Abstract
A high efficiency thermal management system for solid state
lighting devices includes an LED heat sink housing formed by a flat
bottom wall and a sidewall mounted about its periphery that extends
radially outwardly so that the heat sink housing has a
frusto-conical shape. Heat-dissipating pin-shaped fins of differing
lengths depend from the exterior of the angled wall and from the
bottom of the flat bottom wall. The radially inward side of the
angled wall has a highly light-reflective surface for collimating
light. The base of the device provides a housing for driver
electronics. The heat sink housing, the pin-shaped fins, and the
base are collectively contoured so that the system has the overall
size and shape of a type A light bulb.
Inventors: |
Morejon; Israel (Tampa, FL),
Zhai; Jinhui (Oldsmar, FL), Bui; Thong (Tarpon Springs,
FL), O'Sullivan; Evan (Safety Harbor, FL), Swiger;
Jeremy (Tampa, FL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Morejon; Israel
Zhai; Jinhui
Bui; Thong
O'Sullivan; Evan
Swiger; Jeremy |
Tampa
Oldsmar
Tarpon Springs
Safety Harbor
Tampa |
FL
FL
FL
FL
FL |
US
US
US
US
US |
|
|
Assignee: |
LEDnovation, Inc. (Tampa,
FL)
|
Family
ID: |
47562290 |
Appl.
No.: |
12/768,887 |
Filed: |
April 28, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61175116 |
May 4, 2009 |
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Current U.S.
Class: |
313/46; 362/373;
362/294 |
Current CPC
Class: |
F21V
29/81 (20150115); F21V 23/006 (20130101); F21V
29/80 (20150115); F21V 29/83 (20150115); F21V
23/009 (20130101); F21V 17/164 (20130101); F21V
19/0055 (20130101); F21Y 2115/10 (20160801); F21Y
2105/10 (20160801) |
Current International
Class: |
H01K
1/58 (20060101); F21V 29/00 (20060101) |
Field of
Search: |
;313/46
;362/294,373 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO 2009087897 |
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Jul 2009 |
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WO |
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Primary Examiner: Mai; Anh
Assistant Examiner: Santonocito; Michael
Attorney, Agent or Firm: Smith; Ronald E. Smith & Hopen,
P.A.
Claims
What is claimed is:
1. A solid state lighting device, comprising: a driver housing
adapted for electrical communication with a voltage source; a heat
sink having a frusto-conical shape defined by a flat, disc-shaped
bottom wall having a circular perimeter and an annular sidewall
mounted about the circular perimeter of said flat, disc-shaped
bottom wall and projecting upwardly and radially outwardly
therefrom; a plurality of individual heat-radiating fins of
differing lengths formed integrally with and depending from said
disc-shaped bottom wall of said heat sink; each fin of said
plurality of individual heat-radiating fins having a straight
configuration in the form of a pin so that ambient air surrounds
each pin and is free to flow between contiguous pins; said heat
sink mounted in surmounting relation to said driver housing; a
diffusion dome mounted in surmounting relation to said heat sink;
said heat sink including said plurality of individual
heat-radiating fins, and said driver housing collectively having a
size and shape substantially equal to a size and shape of a
conventional class "A" type of light bulb; said class "A" type of
light bulb having a longitudinal axis of symmetry; said disc-shaped
bottom wall of said heat sink being disposed normal to said
longitudinal axis of symmetry; each fin of said plurality of
heat-radiating fins having a longitudinal axis of symmetry parallel
to said longitudinal axis of symmetry of said class "A" type of
light bulb; each fin of said plurality of individual heat-radiating
fins being uncovered and surrounded by ambient air; said plurality
of individual heat-radiating fins arranged in rows and columns and
being parallel to one another and being equidistantly spaced apart
from one another so that air may flow in multiple directions
between said heat-radiating fins, thereby transferring heat away
from said heat sink, said multiple directions including air flow
about a three hundred sixty degree (360.degree.) circumference of
said flat, disc-shaped bottom wall of said heat sink, thereby
transferring heat away from said heat sink at any rotational
orientation of said heat sink; said air flow being generally normal
to the longitudinal axis of symmetry of each fin of said plurality
of heat-radiating fins; and said arrangement of heat-radiating fins
including a straight alignment of fins every sixty degrees about
the circular perimeter of said heat sink.
2. The solid state lighting device of claim 1, further comprising:
said annular sidewall having a light-reflective surface on a
radially inwardly facing side thereof for collimating light.
3. The solid state lighting device of claim 2, further comprising:
a flat printed circuit board adapted to support a plurality of
light-emitting devices; said flat printed circuit board being
secured in overlying relation to said flat, disc-shaped bottom wall
of said heat sink.
4. The solid state lighting device of claim 3, further comprising:
said flat, disc-shaped bottom wall of said heat sink having an
elongate slot formed therein, said elongate slot adapted to receive
an LED cable harness; and an aperture formed in said flat,
disc-shaped bottom wall at a radially innermost end of said
elongate slot.
5. The solid state lighting device of claim 3, further comprising:
said driver housing having a top piece and a bottom piece; said top
piece including a flat, round plate and a cylindrical member
mounted atop said flat, round plate in centered relation thereto;
and means for interconnecting said top piece of said driver housing
to said flat, disc-shaped bottom wall of said heat sink.
6. The solid state lighting device of claim 5, further comprising:
said means for interconnecting said top piece of said driver
housing to said flat, disc-shaped bottom wall of said heat sink
being a plurality of apertures formed in said flat, disc-shaped
bottom wall in encircling relation to a center of said flat,
disc-shaped bottom wall and a plurality of mating tangs formed in a
top wall of said top piece of said driver housing.
7. The solid state lighting device of claim 5, further comprising:
said bottom piece including a frusto-conical sidewall and a
cylindrical base depending from said frusto-conical sidewall; a
driver electronics printed circuit board having an upper end
secured to said top piece and having a lower end received within a
hollow interior of said bottom piece.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a nonprovisional of U.S. provisional patent
application No. 61/175,116 filed May 4, 2009 which is hereby
incorporated by reference into this disclosure.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, generally, to the art of solid state
lighting devices. More particularly, it relates to a solid state
lighting device having heat dissipating fins.
2. Description of the Prior Art
Conventional solid state lighting devices vary in size and shape,
depending upon the type of incandescent or compact fluorescent
(CFL) light bulb they are designed to replace as well as the
intended location and use of the devices.
Thermal management of solid state devices is critical to
performance and life of the light emitting diodes (LEDs) used in
solid state lighting devices. Natural convection is most often
relied on to keep the devices cool. However, with rapidly advancing
LED technology, traditional heat sink housings for smaller, "A"
shaped and similar bulbs are limited in the amount of heat that can
be rejected.
Conventional heat sink housings typically incorporate contoured or
straight fins extending radially outwardly from a longitudinal axis
of symmetry of the bulb. Such fins are limited in the amount of
available surface area for natural convection due to the allowable
bulb envelope and the space required for driver electronics.
Thermal densities of the LEDs have reached a critical point where
the means of cooling must be improved.
Thus there is a need for an improved cooling means for solid state
lighting devices.
There is a need as well for a solid state lighting device that fits
within the envelope and replaces equivalent incandescent and CFL
bulbs of various "A" type sizes such as A15, A17, A19, A21, A23,
and the like.
A need also exists for a dual-purpose support structure that
facilitates mounting of LEDs, diffusers, driver electronics, and a
lamp base, and that provides a means of heat rejection.
However, in view of the art considered as a whole at the time the
present invention was made, it was not obvious to those of ordinary
skill in the art how the needed improvements could be provided.
SUMMARY OF THE INVENTION
The long-standing but heretofore unfulfilled need for an improved
solid state lighting device is now met by a new, useful, and
non-obvious invention.
The novel solid state lighting device includes a driver housing
adapted for electrical communication with a voltage source, a heat
sink, and a plurality of heat-radiating fins of differing lengths
formed integrally with and depending from the heat sink. Each fin
has a pin shape. The heat sink is mounted in surmounting relation
to the driver housing and a diffusion dome is mounted in
surmounting relation to the heat sink.
The diffusion dome, the heat sink including the plurality of fins,
and the driver housing collectively have a size and shape
substantially equal to a size and shape of a conventional "A" type
of light bulb.
The heat sink has a frusto-conical shape defined by a flat bottom
wall. An annular sidewall is mounted about the periphery of the
flat bottom wall and projects upwardly and radially outwardly
therefrom. The sidewall has a highly light-reflective surface on a
radially inwardly facing side thereof for collimating light.
A flat printed circuit board adapted to support a plurality of
light-emitting devices is secured in overlying relation to the flat
bottom wall. The flat bottom wall has an elongate slot formed
therein that is adapted to receive an LED cable harness. An
aperture is formed in the radially innermost end of the elongate
slot.
The driver housing has a top piece and a bottom piece. The top
piece includes a flat, round plate having a cylindrical member
mounted atop it in centered relation thereto. Means are provided
for interconnecting the top piece of the driver housing to the flat
bottom wall of the heat sink housing.
The bottom piece of the driver electronics housing includes a
frusto-conical sidewall and a cylindrical base depending therefrom.
A driver electronics printed circuit board has an upper end nested
within and secured to the hollow interior of the top piece and a
lower end received within and secured to a hollow interior of the
bottom piece.
The primary object of the invention is to advance the art of solid
state light emitting devices by providing a high efficiency solid
state lighting device that incorporates a highly effective thermal
management system.
A closely related object is to provide a high efficiency solid
state lighting device having the shape and size of a conventional
incandescent light bulb.
A more specific object is to provide a solid state lighting device
having a diffusion dome, a heat sink housing, heat-dissipating
fins, a driver electronics housing and a lamp base that
collectively have the size and shape of a conventional incandescent
light bulb.
These and other important objects, advantages, and features of the
invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction,
combination of elements, and arrangement of parts that will be
exemplified in the disclosure set forth hereinafter and the scope
of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the
invention, reference should be made to the following detailed
disclosure, taken in connection with the accompanying drawings, in
which:
FIG. 1 is a side elevational view of a solid state lighting device
that incorporates the novel thermal management system;
FIG. 2 is an exploded view of the novel thermal management
system;
FIG. 3 is a top plan view thereof;
FIG. 4 is a side elevational view thereof;
FIG. 5 is a top plan view of the novel heat sink;
FIG. 6 is a top perspective view of the novel heat sink;
FIG. 7 is a bottom perspective view of the novel heat sink;
FIG. 8 is a side elevational view of the novel heat sink;
FIG. 9 is a bottom plan view of the novel heat sink;
FIG. 10 is a top plan view of the novel driver housing;
FIG. 11 is a side elevational view of the novel driver housing;
FIG. 12 is a bottom plan view of the novel driver housing;
FIG. 13 is a top perspective view of the novel driver housing;
and
FIG. 14 is a bottom perspective view of the novel driver
housing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The novel thermal management system for a solid state lighting
device is depicted in FIG. 1 as a whole by the reference numeral
10. It includes dome 12, heat sink housing 14, and driver
electronics housing 16. The novel solid state lighting device is
sized and shaped to replace type "A" type incandescent and compact
fluorescent light (CFL) bulbs.
Referring now to the exploded view of FIG. 2, thermal management
system 10 includes printed circuit board (PCB) 18 upon which is
mounted a plurality of light emitting devices (LEDs) 20. PCB 18 is
disc-shaped and overlies disc-shaped flat wall 22 when novel system
10 is fully assembled. Flat wall 22 is an integral part of heat
sink housing 14 and is formed of a material having a high
coefficient of heat transfer, i.e., that provides maximum heat
conduction.
Annular sidewall 24 is an integral part of flat wall 22. It
projects upwardly from flat wall 22 at a small radially outward
angle so that heat sink housing 14 has a frusto-conical shape. The
radially inward side of annular sidewall 24 is covered by a highly
light-reflective surface that performs the function of collimating
light before its exits device 10 through dome 12.
Elongate slot 22a is formed in flat wall 22, extending from the
center thereof in a radially outwardly direction and having a
radially outermost end disposed in closely spaced relation to
annular sidewall 24. Slot 22a and aperture 22b at its radially
innermost end enables routing of an LED cable harness, not
depicted.
In this particular illustrative embodiment, apertures 18a are
formed in PCB board 18 and corresponding apertures 18b are formed
in flat wall 22 so that a plurality of fasteners such as screws 26
may be used to secure PCB board 18 in overlying relation to flat
wall 22. PCB board 18 may also be press fit or otherwise secured
into said overlying relation to said flat wall 22.
A third plurality of apertures 23 is also formed in flat wall 22
and encircles a longitudinal axis of symmetry of device 10.
Apertures 23 receive mounting tangs 25 that surmount top piece 30
of driver housing 16 to secure said driver housing to flat wall 22
of heat sink 14. Many other suitable fastening means may be
employed to securely interconnect driver electronics housing 16 to
heat sink housing 14.
A suitable fastening means engages dome 12 to heat sink housing
14.
Pin fins 34, each of which has a round transverse cross-section,
have differing lengths. The radially outermost pin fins 34 depend
from the exterior side of frusto-conical sidewall 24. The pin fins
radially inwardly of the radially outermost pin fins depend from
flat wall 22. Pin fins 34 protrude to facilitate heat rejection due
to natural convection. Pin fins 34 are drafted from top to bottom
to facilitate manufacturing.
As best depicted in FIG. 9, no pin fins are provided in center
region 15 of heat sink 14 to provide space for driver electronics
housing 16 and its mating connections. More particularly, mounting
tangs 25 surmount top piece 30 of driver electronics housing 16 as
aforesaid and pin-free center region 15 accommodates said top piece
30 so that mounting tangs 25 may engage apertures 23 as aforesaid.
As depicted in FIGS. 7-9, the heat-radiating fins are individually
formed and arranged in rows and columns and are parallel to one
another and are equidistantly spaced apart from one another so that
air freely flows in any direction including generally horizontal
directions between said individual heat-radiating fins, thereby
transferring heat away from heat sink 14. More particularly, as may
be seen from an inspection of said Figures, cooling air may flow
between said individual fins from six (6) directions at sixty
degree) (60.degree. intervals about the three hundred sixty degree
(360.degree.) circumference of the heat sink, thereby transferring
heat away from said heat sink at any heat sink rotational
orientation. Accordingly, heat sink 14 can be positioned in any
rotational orientation and cooling air will flow between the
individual fins.
Driver electronics housing 16 mates to the underside of flat wall
22 in pin fin-free region 15. The frusto-conical surface of housing
16 continues the contour formed by the pins fins that define the
classic "A"-type lamp shape.
Aperture 30a is formed in top piece 30 in coincidence with the
longitudinal axis of symmetry of system 10. It enables an
undepicted LED cable harness to be electrically connected to PCB
board 18.
Top piece 30 of driver electronics housing 16 includes cylindrical
member 38 mounted on flat plate 40, centrally thereof. Gussets 42
are equidistantly and circumferentially spaced around cylindrical
member 38 to enhance its structural integrity.
Driver electronics are mounted on upstanding PCB 44. Protuberance
44a is nested within the hollow interior of cylindrical member 38
when system 10 is fully assembled. PCB 44 is secured when the top
and bottom pieces that form housing 16 are assembled.
Driver electronics housing 16 further includes bottom piece 46
having frusto-conical section 46a and cylindrical section 46b. A
plurality of slots, not depicted, may be formed in frusto-conical
section 46a to provide air flow inside driver electronics housing
16.
As depicted in FIG. 1 and as depicted and numbered in FIG. 4, the
respective contours of frusto-conical section 46a and cylindrical
section 46b cooperate with the shape of pin fins 34 to produce the
"A" type contour. The longest pin fins have flat bottoms that do
not extend below the upper plane of frusto-conical section 46a. The
shorter pin fins have bevels formed in their respective lowermost
ends to produce said type "A" contour.
Printed circuit board 44 is flat and its upper part 44b has beveled
edges to match the contour of frusto-conical section 46a. The
straight lower part 44c of PCB 44 is received within the hollow
interior of cylindrical section 46b as indicated in FIG. 2.
Cylindrical section 46b is integrally formed with frusto-conical
section 46a and depends therefrom. It provides means for mounting
the lamp base in a socket. In the embodiment of FIG. 1, a
conventional Edison screw 47 is mounted on cylindrical section
46b.
FIG. 3 is a top plan view depicting PCB 18 secured by screws 26 to
flat wall 22 of heat sink 14.
FIG. 4 depicts how pin fins 34 are collectively sculpted to fit
within the envelope of a type A lighting device.
FIG. 5 more clearly depicts aperture 22b at the radially innermost
end of slot 22a formed in flat wall 22 of heat sink 14.
FIG. 6 is a top perspective view of heat sink 14. Annular ledge 14a
provides a mount for dome 12 as perhaps best depicted in FIG.
1.
FIG. 7 is a bottom perspective view of heat sink 14, depicting how
the radially outermost pin fins 34 depend from the exterior of
frusto-conical sidewall 24 of heat sink and how the interior pin
fins depend from the bottom of flat wall 22 of said heat sink.
The side elevational view of FIG. 8 also depicts the radially
outermost pin fins 34 formed integrally with the exterior side of
frusto-conical sidewall 24 and the interior pin fins depending from
flat wall 22. From the bottom plan view of the novel heat sink and
pin fins provided in FIG. 9, it is clear that air flow follows a
path of travel that is generally normal to the longitudinal axis of
each pin fin. The novel arrangement of heat-radiating fins includes
a straight alignment of fins every sixty degrees (60.degree.) about
the circular perimeter of the bottom wall of the heat sink.
Top part 30 of driver electronics housing 16 is depicted in top
plan view in FIG. 10.
The fully assembled driver electronics housing 16 is depicted in
side elevational view in FIG. 11, in bottom plan view in FIG. 12,
in top perspective in FIG. 13 and in bottom perspective in FIG.
14.
Lighting device having novel thermal management system 10 is light
in weight and provides better thermal management properties than
conventional heat sink housings used in solid state lighting
devices.
The novel heat sink has an increased surface area for convection
cooling and provides nearly equal space for driver electronics. It
also provides a continuous thermal interface for PCB 18 and
includes integrated reflector surface on the radially inward side
of angled annular sidewall 24 for collimating light output as
aforesaid.
System 10 includes means for holding and retaining all components
of a working solid state lighting bulb optimized for natural
convection and the equivalent lumen output of a twenty-five to one
hundred watt (25-100 W) incandescent bulb. The novel solid state
lighting device meets the envelope constraints of ANSI C78-20 for
"A" style bulbs in the particular sizes and wattages contained
therein.
It will thus be seen that the objects set forth above, and those
made apparent from the foregoing disclosure, are efficiently
attained and since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matters contained in the foregoing disclosure
or shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
that, as a matter of language, might be said to fall
therebetween.
* * * * *